端粒酶抑制剂对舌癌细胞株端粒酶活性和细胞周期的作用

目的研究舌癌细胞经端粒酶抑制剂(3′-叠氮-3′-脱氧胸腺核苷,AZT)处理后端粒酶活性和细胞周期的变化情况.方法采用端粒重复序列扩增(telomeric repeat amplification protocol,TRAP)-PCR-ELISA方法检测舌癌细胞系Tca8113经AZT作用前后端粒酶活性的变化,流式细胞仪分析细胞周期变化.结果AZT可显著抑制Tca8113细胞端粒酶活性,而且这种抑制效应有浓度依赖性(经0.3、0.6、1.0、1.5 mol/L的AZT处理12小时的Tca8113端粒酶活性分别为0.69±0.03、0.61±0.08、0.53±0.11、0.50±0.02,未经AZT处理的Tca8113细胞端粒酶活性为0.76±0.06).流式细胞仪结果显示经AZT处理的细胞G2/M期含量显著增高(62.8%),未处理组为19.7%(P＜0.05).结论AZT可以明显抑制舌癌细胞的端粒酶活性,并使肿瘤细胞停滞在G2/M期,有抗肿瘤的作用.     

Determination of telomerase activity in squamous cell carcinoma of the penis

Telomerase activity was studied in 51 penile carcinomas, and detected in all samples from 3 patients with verrucous carcinoma, in 85.4% (41/48) of invasive carcinomas, in 81.8% (9/11) of adjacent non-cancerous skin and in 80% (8/10) of adjacent non-cancerous corpus cavernosum. All skin and corpus cavernosum samples from patients with prostatic carcinoma were found to be telomerase negative. Our results indicate a correlation between frequency of telomerase activity and grade of penile carcinoma. The finding of telomerase activity in skin and corpus cavernosum samples adjacent to tumor suggests that unidentified local factors may modulate telomerase activity in normal tissues.     

食管鳞癌组织端粒酶亚基的表达及端粒酶活性的关系

目的　探讨食管鳞癌组织中端粒酶活性、端粒酶逆转录酶 (h TERT)及端粒酶相关蛋白 - 1(TP- 1)的表达及其关系。方法　应用 TRAP-银染法对 45例食管鳞癌组织端粒酶活性的检测 ,同时应用原位杂交对癌组织切片进行 h TERT、TP- 1的 m RNA表达的检测。结果　癌组织端粒酶活性阳性率为 82 .2 %。癌组织中不同分化程度的端粒酶活性差异无显著性 (P>0 .0 5 )。有淋巴结转移者癌组织端粒酶活性明显高于无淋巴结转移者 ,差异有显著性(P<0 .0 5 )。癌组织中 h TERTm RNA表达的阳性率为 6 4.4%,TP- 1的阳性率为 6 2 .2 %。 h TERT的 m RNA表达与端粒酶活性密切相关 ,而 TP- 1的 m RNA表达与端粒酶活性无相关。结论　食管鳞癌组织中端粒酶活性及h TERT、TP- 1的 m RNA表达均较高。端粒酶活性与淋巴结转移有关。 h TERT与端粒酶活性有密切关系。     

Elevated N-myristoyltransferase activity and expression in oral squamous cell carcinoma

N-myristoyltransferase (NMT) catalyzes the myristoylation of proteins involved in signal transduction, cellular transformation, differentiation, proliferation and oncogenesis. In this study, we report for the first time on the elevated NMT activity in oral squamous cell carcinoma (OSCC). Increased activity is marked with increased staining for NMT in the OSCC samples compared to the normal adjacent tissues. In addition, we observed increased staining for the N-myristoyltransferase inhibitor protein 71 (NIP71) in the OSCC samples compared to the control tissues. These findings suggest the regulatory relationship between NMT and NIP71 during tumorigenesis. It is possible that the increased activity results in the overexpression of NIP71 in an effort to control NMT activity.     

Keratosis follicularis of the oral mucosa with oral squamous cell carcinoma

Darier's disease or keratosis follicularis is a genodermatosis which may involve the oral mucosa. Malignant degeneration is rare. We report the first case of the combined manifestation of oral keratosis follicularis and oral squamous cell carcinoma and discuss the possible involvement of ATP2A2 (located in 12q23-24.1) which encodes the sarco/endoplasmic reticulum Ca(2+)-ATP isoform 2 (SERCA2), in the pathogenesis.     

Resistance to telomerase inhibition by human squamous cell carcinoma cell lines

Telomeres are nucleoprotein structures at the ends of chromosomes that are composed of a repetitive G rich sequence and telomeric binding proteins. Telomeres prevent the degradation of chromosomal ends and protect against inappropriate recombination. Telomere attrition involves a tumor suppressor pathway that limits the replication of premalignant cells. The loss of telomeric DNA with each round of replication leads to growth arrest accompanied by senescence or apoptosis. Many tumor cells activate the telomerase gene to bypass senescence. Telomerase is a multisubunit ribonucleoprotein that uses an RNA template to catalyze the addition of telomeric DNA to chromosomal ends. Overexpression of the TERT subunit leads to telomere lengthening and extension of the replicative lifespan. Dominant-negative telomerase has been shown to inhibit telomerase activity in many tumor cell lines, and this is associated with telomere shortening and apoptosis. Additionally, pharmacological telomerase inhibitors have been developed which lead to progressive telomere shortening and programmed cell death. In this study, we report a series of human squamous cell carcinoma cell lines that have high telomerase activity and short telomeres. Dominant-negative telomerase expression and pharmacological telomerase inhibition failed to completely inhibit enzymatic activity which was accompanied by the lack of telomere shortening. These cells continued to proliferate and demonstrated fewer responsive genes when treated with a pharmacological telomerase inhibitor. We concluded that some human squamous cell carcinoma cell lines are resistant to telomerase inhibition.     

Loss of adhesion-regulated proteinase production is correlated with invasive activity in oral squamous cell carcinoma

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity. However, the cellular and biochemical factors that underlie locoregional and distant spread of the disease are poorly understood. Invasion of OSCC requires multiple cellular events including dissolution of cell-cell junctions, basement membrane attachment, extracellular matrix proteolysis, and migration. METHODS: We evaluated these properties in vitro using premalignant gingival keratinocytes (ppl26) and two OSCC lines (SCC15 and SCC68). Expression of adhesion molecules integrins and cadherins, cytoplasmic intermediate filaments (IF) vimentin and keratin as well as matrix degrading proteins were evaluated. Moreover, regulation of protease production by adhesion molecules was tested. RESULTS: All cell lines contained comparable levels of the epithelial cell-cell adhesion molecule, E-cadherin. Differential expression of cytoplasmic IF was evident between premalignant pp126 cells and OSCC cell lines. Expression levels of the alpha3beta1 integrin, utilized for attachment to laminin-5 and other matrix proteins, was high in SCC68 cells, moderate in SCC15 cells, and low in ppl26 cells. alpha3beta1 integrin clustering up-regulates expression of urinary-type plasminogen activator (uPA) in ppl26 cells via a mechanism involving ERK activation. Both ppl26 and SCC15 cells were responsive to alpha3beta1 clustering, resulting in enhanced uPA expression. However, basal uPA levels were high in SCC68 cells and integrin clustering did not further stimulate uPA production. ERK was constitutively activated in SCC68 cells and treatment of cells with an inhibitor of ERK activation (PD98059) reduced uPA expression. Consistent with the enhanced proteolytic potential, SCC68 cells readily penetrated Matrigel and invasion was blocked by an anticatalytic uPA antibody. CONCLUSIONS: These data suggest that loss of adhesion-regulated proteinase production may lead to elevated pericellular proteinase activity and coincident alterations in cytoskeletal IF protein expression, thereby contributing to the invasive potential of OSCC.     

Factors associated with diagnostic delay of oral squamous cell carcinoma

Shortening the diagnostic delay from the onset of symptoms to the final diagnosis leads to early cancer detection and a reduced incidence of advanced cases. To analyze factors contributing to delays in the diagnosis of oral cancer, information was collected from the medical charts of 152 consecutive patients with oral squamous cell carcinoma, and factors associated with diagnostic delay were examined retrospectively. No characteristic was significantly associated with delay caused by patients. Referral by a non-initial professional, initial visit to a dentist, T1 cancer, and the presence of an ulcerative lesion were significantly associated with delay caused by the initial professionals. Patients with N0 were significantly associated with diagnostic delay caused by the final professional. These results re-emphasize the important role of the initial professional, particularly the dentist, and the diagnostic difficulty posed by ulcerative lesions and small-sized or early-stage oral cancer.     

Survivin expression in oral squamous cell carcinoma

A series of 110 cases of oral squamous cell carcinoma (SCC) together with six lymph node and one distant metastatic lesions was analysed for expression of survivin, a recent apoptosis inhibitor, by immunohistochemistry and Western blotting. In total, 91 cases (82.7%) of carcinoma and all metastasis (seven cases, 100%) were positive for survivin expression, with weighted survivin scores ranging from 1 to 4. In contrast, normal oral epithelium did not express survivin. There was no significant correlation between survivin expression and age, sex, tumour size, the presence of lymph node and distant metastases. Survivin expression was increased in poorly differentiated tumours, even if differences were not statistically significant. In contrast, when analysed for prognostic significance, patients with low survivin expression had statistically significant better survival rates than the group with high survivin expression (P<0.05). These data suggest that survivin expression may identify cases of oral SCC with more aggressive and invasive phenotype.     

Analysis of fluorescence in oral squamous cell carcinoma

This study was carried out to examine the spectral properties of the red fluorescence emitted from oral squamous cell carcinoma (SCC). Fluorescent samples obtained from oral cancers induced in hamsters, human oral SCCs, and the medium from cultured oral cancer cell lines were analyzed with a spectrofluorometer with excitation at 404 nm. The spectral profile of the experimentally induced cancers changed with increasing malignancy: peaks at 634 and 672 nm increased and peaks at 520 and 582 nm decreased. A reduction in fluorescence intensity at 582 nm and a rise of intensity at 634 nm were commonly observed in the experimental, clinical, and cell line samples, and the ratio of the fluorescence intensity at 582 nm over that at 634 nm was consistent in all samples. These results suggested that the red fluorescence was emitted by porphyrin, which we believe to be produced by oral SCCs and to accumulate inside or on the surface of cancer tissues in greater amounts with progressing malignancy.     

Diagnosis and therapy of oral squamous cell carcinoma

Oral squamous cell carcinoma ranks among the top ten most common cancers worldwide. Despite the success in diagnosis and therapy during the past 30 years, oral squamous cell carcinoma still belongs to the tumor types with a very unfavorable prognosis. In an effort to identify genomic alterations with prognostic relevance, we applied the comparative genomic hybridization technique on oral squamous cell carcinoma. The tumors exhibited from five up to 47 DNA copy number alterations, indicating a considerable degree of genomic imbalance. Out of 35 tumors, 19 showed a gain of chromosome band 7p12. Genomic imbalances were investigated by hierarchical cluster analysis and clustered image mapping to investigate whether genomic profiles correlate with clinical data. Results of the present investigation show that profiling of genomic imbalances in general, and especially of the epidermal growth factor receptor (EGFR) on 7p12, may be suitable as prognostic factors. In order to identify small-molecule inhibitors for EGFR, we established a database of 531 natural compounds derived from medicinal plants used in traditional Chinese medicine. Candidate compounds were identified by correlation analysis using the Kendall tau-test of IC50 values of tumor cell lines and microarray-based EGFR mRNA expression. Further validation was performed by molecular docking studies using the AutoDock program with the crystal structure of EGFR tyrosine kinase domain as docking template. We estimate these results will be a further step toward the ultimate goal of individualized, patient-adapted tumor treatment based on tumor molecular profiling.     

Expression of emmprin by oral squamous cell carcinoma

A transmembrane glycoprotein recently identified on some tumor cells, extracellular matrix metalloproteinase inducer (EMMPRIN), has been shown to induce metalloproteinase (MMP) production by peritumor fibroblasts (PTF). We examined biopsy specimens of normal human oral mucosa and oral squamous cell carcinoma (SCC) for expression of EMMPRIN. In normal mucosa, EMMPRIN was expressed at the cell membrane throughout the epithelium with a slight enhancement along the basal cell layer. In oral SCC, EMMPRIN was expressed at the cell membrane throughout the entire lesion. Immunofluorescence microscopy localized EMMPRIN to the cell membrane in a highly invasive oral SCC cell line in agreement with our in vivo observations. Function-blocking antibodies to EMMPRIN significantly inhibited oral SCC cell migration on tenascin-C (TN-C) and fibronectin as well as invasion through a reconstituted basement membrane (RBM). We previously showed that soluble factors from SCC cells and PTF are required for deposition of a TN-C matrix. To determine whether EMMPRIN may modulate the release or expression of these soluble factors, we again used function-blocking antibodies. Antibodies to EMMPRIN completely inhibited the organization of TN-C matrices and partially reduced the deposition of FN matrices by oral SCC cell /PTF co-cultures. In addition, antibodies to EMMPRIN perturbed the expression of MMP-2. Moreover, antibodies to MMP-2 perturbed oral SCC cell invasion of an RBM by approx. 75%. Our results demonstrate that EMMPRIN is highly expressed in oral SCC, facilitates tumor cell motility, and mediates TN-C matrix deposition. Taken together, these results suggest that EMMPRIN may help regulate oral squamous cell carcinoma invasion.     

Characterization of autofluorescence in oral squamous cell carcinoma

This study was carried out to evaluate the clinical characteristics of autofluorescence in oral squamous cell carcinoma (SCC) and analyze the fluorescent substances using high-performance liquid chromatography (HPLC). Fifty of 55 oral SCCs (91%) emitted orange or red fluorescence, which was recorded by fluorescence photography. The intensity of the fluorescence significantly correlated with the T and N categories of the cancers, but did not show statistical difference for the types of clinical appearance and primary sites. Protoporphyrin and coproporphyrin were identified as the fluorescent substance in the SCC samples, and the elution patterns on HPLC revealed some porphyrin compounds as specific to oral cancer. These results suggest that the autofluorescence in oral SCC correlates with the progression of lesions, and that fluorescent substances such as protoporphyrin are produced in association with the cancerous tissue.     

Cytokeratin alteration in oral leukoplakia and oral squamous cell carcinoma

Intermediate filaments are involved in cell migration and intracellular signal transduction pathways. In a variety of organs, the expression of distinct intermediary filaments are further associated with distinct steps of malignant transformation. In this study, we seeked to define the cytokeratin (Ck) expression pattern in oral leukoplakia and oral squamous cell carcinoma (OSCC). One hundred and ninety-two patients with OSCC, 117 patients with oral leukoplakia without dysplasia (OL) and 23 with oral leukoplakia with dysplasia (squamous intraepithelial neoplasia) (OLD) of the oral cavity were investigated for the immunohistochemical expression of Ck 5-6, Ck 8/18, Ck 1 Ck 10, Ck 14, Ck 19 using the tissue microarray technique. Correlations between clinical features and the expression of cytokeratins were evaluated statistically by chi2 tests. The expression of Ck 8/18, Ck 19 and Ck 1 was seen in 3.1% (Ck 8/18), 12.5% (Ck 19), 75.4% (Ck 1) of all leukoplakias, 1.0% (Ck 8/18), 9.4% (Ck 19), 76.8% (Ck 1) in OL, 13.0% (Ck 8/18), 27.3% (Ck 19), 68.4% (Ck 1) in OLD and was significantly associated with the degree of dysplasia (Ck 8/18 p<0.01; Ck 19 p<0.01; Ck 1 p<0.01) and the acquisition of invasive growth properties. The highest frequencies were observed in invasive squamous cell carcinomas. The expression of Ck 8/18 and Ck 19 in transformed oral lesions can be regarded as an early feature in the pathogenesis of invasive OSCC. However, the aberrant expression of Ck 8/18 and Ck 19 in an even higher frequency in invasive carcinomas characterizes the expression of typical glandular cytokeratins as a general progression marker in squamous cell carcinomas. These results can be interpreted as first hints that oral leukoplakias with an expression of Ck 8/18 or 19 independent of dysplasia, should be resected totally since they might indicate an increased progression potential.     

Blood telomerase activity and its correlativity with non-small cell lung carcinoma

From the viewpoint of oncology, an importantcharacteristic of cancer is that cell schizogenesisbecomes out of control[1,2]. Recently, lots of researchesfocus on telomerase. The activation of telomerase isessential for cell to get athanasia, which is the key step incancer pathogenesis, while the normal cell lacks suchenzyme activity[3-5]. Thus, telomerase theory for cancerpathogenesis occurred. Lung cancer is a malignant disease with highincidence, which increases rapidly with theindustrializat…